Image inspection device

ABSTRACT

An image inspection device has a first suction conveyance unit which is arranged on the upstream side with a conveyance surface as an upper surface, a second suction conveyance unit which is arranged on the downstream side with a conveyance surface as a lower surface to make the conveyance surface continuous from the upstream side, a first inspection section which inspects an image on a front surface of an inspection object which is conveyed to the first suction conveyance unit and a second inspection section which inspects an image on a back surface of the inspection object which is conveyed to the second suction conveyance unit. The inspection object is conveyed in a state of being sucked and held on the first and second suction conveyance units and therefore is stable in position and posture in conveyance and an expected accuracy is maintained in inspection performed by the first and second inspection sections.

TECHNICAL FIELD

The present invention concerns an image inspection device which inspects images which are formed on a sheet-shaped inspection object and particularly relates to the image inspection device which is able to inspect the images which are formed on both front and back surfaces of the inspection object with high accuracy while conveying the inspection object in one direction without inverting the inspection object.

BACKGROUND ART

In an image forming apparatus which is equipped with a function of forming the images on both the front and back surfaces of a sheet, there are cases where it becomes necessary to inspect the images on both the front and back surfaces of the sheet while conveying the sheet. In such a case, it is possible to adopt such a configuration that one camera which captures the images formed on the sheet and one sensor are installed, an inverting section is installed on a path along which the sheet is conveyed, the image on the front surface is inspected by the sensor and thereafter the sheet is inverted so as to again pass under the sensor again and the image on the back surface of the sheet is inspected. However, a method of conveying and inverting the sheet by the inverting section in this way has such a problem that a mechanism is complicated and is increased in size.

An invention of an image forming apparatus is disclosed in Patent Literature 1. The image forming apparatus is equipped with a jam recovery device and is of the type that in a case where the top sheet which is jammed is located on the downstream side of a sheet inspection device 150, printing is resumed from images which are formed on the top jammed sheet on condition that an instruction to resume printing is issued from a user.

The image forming apparatus has a camera unit 230. Then, a sheet conveyance path 223 along which the sheet is conveyed in one direction from the upstream to the downstream is installed on the camera unit 230 and two cameras 231 and 232 are arranged at vertically aligned positions above and under the path 223 so as to face each other. That is, unlike the configuration that the images on both the front and back surfaces of one sheet are inspected by using one camera and the inverting section on the conveyance path, in the camera unit 230, the sheet is conveyed in one direction without being inverted and the two cameras 231 and 232 read out the respective images on upper and lower surfaces (the front and back surfaces) of the conveyed sheet respectively while the sheet is being conveyed. The sheet inspection device 150 inspects the images which are printed on the sheet by using captured images on the sheet which are sent from the camera unit 230.

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2018-31963 SUMMARY OF INVENTION Technical Problem

In the camera unit of the image forming apparatus which is disclosed in Patent Literature 1, the two cameras are arranged at the vertically aligned positions with the sheet conveyance path being sandwiched between the two cameras so as to face each other and the camera unit is configured that images on vertically aligned places on both the front and back surfaces of the sheet are captured by the two cameras. Therefore, at positions on the sheet conveyance path where the cameras are installed, it is necessary to expose both the front and back surfaces of the sheet relative to the cameras across sufficiently wide areas. However, when large openings are formed in both upper and lower surfaces of a section of the sheet conveyance path where the cameras are arranged in order to bring both the front and back surfaces of the conveyed sheet into largely exposed states, guidance and holding of the sheet which is conveyed are not sufficiently conducted and the position of the sheet fluctuates while the sheet is being conveyed. Therefore, there is a problem of the possibility that an image capturing accuracy by the camera may be lowered.

The present invention has been made in view of such related art and an issue thereof and aims to provide an image inspection device which is able to inspect images on both front and back surfaces of a sheet-shaped inspection object while the sheet-shaped inspection object is being stably conveyed in one direction with no need of using a complicated mechanism which inverts the sheet-shaped inspection object.

Solution to Problem

An image inspection device according to a first aspect of the present invention includes a first conveyance unit which is arranged in such a manner that a conveyance surface on which a sheet-shaped inspection object is conveyed is located on an upper surface side, a second conveyance unit which is arranged adjacent to the conveyance surface of the first conveyance unit along a conveyance object conveyance direction in such a manner that a conveyance surface on which the sheet-shaped inspection object is conveyed is located on a lower surface side, a first inspection section which inspects an image on a front surface of the inspection object which is conveyed by the first conveyance unit, and a second inspection section which inspects an image on a back surface of the inspection object which is conveyed by the second conveyance unit.

Advantageous Effects of Invention

According to the image inspection device according to the first aspect of the present invention, the inspection object is stably conveyed by being held on the upper surface side of the first conveyance unit, for example, by suction and bonding, is stably conveyed by being held on the lower surface side of the second conveyance unit, and delivery of the inspection object between the first conveyance unit and the second conveyance unit is stably performed. Consequently, since the position and the posture of the inspection object which is being conveyed are stabilized, an expected accuracy is maintained in inspection by the first inspection section and the second inspection section.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall configuration diagram illustrating one example of an image forming system which includes an image inspection device according to one embodiment of the present invention;

FIG. 2 is a schematic configuration diagram illustrating one example of the image inspection device according to the embodiment of the present invention;

FIG. 3 is a schematic configuration diagram illustrating one example of the image inspection device which is illustrated by further adding support sections for inspection sections to the schematic configuration diagram in FIG. 2;

FIG. 4 is a front view illustrating one example of the image inspection device according to the embodiment of the present invention;

FIG. 5 is a perspective view illustrating one example of the image inspection device according to the embodiment when seen diagonally from above;

FIG. 6 is a perspective view illustrating one example of the image inspection device according to the embodiment when seen diagonally from below;

FIG. 7 is a perspective view illustrating one example of upstream-side suction conveyance unit, inspection section and so forth of the image inspection device according to the embodiment of the present invention when seen diagonally from above;

FIG. 8 is a perspective view illustrating one example of the suction conveyance unit and the inspection section of the image inspection device according to the embodiment of the present invention when seen diagonally from below;

FIG. 9 is a perspective view illustrating one example of upstream side holding section and inspection section of the image inspection device according to the embodiment of the present invention when seen diagonally from below;

FIG. 10 is an exploded hierarchical perspective view illustrating one example of the upstream side holding section and suction conveyance unit of the image inspection device according to the embodiment of the present invention when seen diagonally from above;

FIG. 11 is a schematic perspective view illustrating one example of a conveyance direction adjustment element which adjusts the conveyance direction that the suction conveyance unit conveys the inspection object to the inspection section in the image inspection device according to the embodiment of the present invention;

FIG. 12 a schematic plan view illustrating one example of the conveyance direction adjustment element which adjusts the conveyance direction that the suction conveyance unit conveys the inspection object to the inspection section in the image inspection device according to the embodiment of the present invention;

FIG. 13 is a schematic front view illustrating a first modified example of the image inspection device according to the embodiment of the present invention;

FIG. 14 is a schematic front view illustrating a second modified example of the image inspection device according to the embodiment of the present invention;

FIG. 15 is a schematic front view illustrating a third modified example of the image inspection device according to the embodiment of the present invention;

FIG. 16 is a schematic front view illustrating a fourth modified example of the image inspection device according to the embodiment of the present invention;

FIG. 17 is a schematic front view illustrating a fifth modified example of the image inspection device according to the embodiment of the present invention;

FIG. 18 is a schematic front view illustrating a sixth modified example of the image inspection device according to the embodiment of the present invention;

FIG. 19 is a perspective view illustrating one example of the upstream-side suction conveyance unit, inspection section and so forth when seen diagonally from above in a seventh modified example of the image inspection device according to the embodiment of the present invention; and

FIG. 20 is a schematic configuration diagram illustrating an eight modified example of the image inspection device according to the embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS <<Basic Structure and Configuration of Image Forming System>>

One embodiment of the present invention will be described with reference to FIG. 1 to FIG. 12.

As schematically illustrated in FIG. 1 by simplifying the structure, one embodiment of the present invention relates to an image forming system which includes a printing device 100, an image inspection device 200 and a post-processing device 300 and particularly has characteristics in the structure of the image inspection device 200 as will be described later.

The printing device 100 has a plurality of inkjet heads 101 which are different from one another in ink color, a conveyance path 102 along which a sheet-shaped medium (a printing sheet) which is an inspection object of the image inspection device 200 is conveyed, and a suction conveyance unit 103 which is installed directly under the inkjet heads 101 in a state of being connected with the conveyance path 102. Illustration of other configurations such as a printing sheet feeding element and so forth is omitted. The post-processing device 300 is a device which performs various post-processing operations on the printing sheet on which images are printed by the printing device 100 and the images so printed are inspected by the image inspection device 200 and then discharges the printing sheet. As contents of the post-processing, sorting work such as sorting, stacking and so forth, stapling, paper insertion, paper folding of various forms, insertion of the paper into an envelope and so forth are included, and it is possible to install the post-processing device 300 which is equipped with necessary functions in accordance with a purpose.

<<Basic Structure and Configuration of Image Inspection Device>>

First, a basic configuration of the image inspection device 200 will be described with reference to FIG. 2 and FIG. 3.

The image inspection device 200 has two suction conveyance units (a first suction conveyance unit 1 and a second suction conveyance unit 2) as elements for conveying a sheet-shaped inspection object (a sheet-shaped medium, that is, the printing paper). First, the first suction conveyance unit 1 will be briefly described within a range which is illustrated in FIG. 2. The first suction conveyance unit 1 has a belt conveyor that a conveyor belt 6 is wound around an upstream-side drive roller 3, an upstream-side driven roller 4, and other two small driven rollers 5. As will be illustrated later in other drawings (for example, see FIG. 5), a resinous intermediate plate 7 is in contact with a lower surface of the upper-side conveyor belt 6 of the first suction conveyance unit 1 and a platen 8 which is a plate material is in contact with a lower surface of the intermediate plate 7. Many through-holes are formed in the conveyor belt 6, the intermediate plate 7, and the platen 8 respectively. Further, a chamber (not illustrated) is attached to a lower surface of the platen 8 and air is sucked by a fan (not illustrated) which is attached to a lower part of the chamber so as to maintain a negative pressure in the chamber. Accordingly, when the fan is driven, the air is sucked into the chamber from the top of the conveyor belt 6 into the chamber through the respective through-holes in the conveyor belt 6, the intermediate plate 7, and the platen 8 and thereby the inspection object is sucked onto the conveyance surface of the conveyor belt 6. Then, when the conveyor belt 6 is driven, it becomes possible to convey the inspection object.

Incidentally, the aforementioned upstream side and downstream side are used in the sense of the upstream side and the downstream side of a direction that the inspection object is conveyed by the suction conveyance units 1 and 2, and the same also applies to the following description.

In the first and second suction conveyance units 1 and 2 of the image inspection device 200, a sheet which is a sheet-shaped medium such as printing paper and so forth is conveyed as an object to be conveyed. Unlike a bag and so forth having a structure that two sheets are stacked, the sheet is sucked to the conveyor belt 6 across the entire surface, a position of the sheet which is vertical to the conveyor belt 6 is fixed within the conveyance surface, and the sheet is conveyed with movement of the conveyor belt 6 in a stable state. Therefore, a height-wise position of the sheet which is conveyed does not fluctuate and a position accuracy of the sheet is high. Accordingly, in a case where a CIS (Contact Image Sensor) and so forth which are shallower than a camera and so forth in depth of field and for which a high arrangement accuracy is required for obtaining an expected reading accuracy is adopted as an element for inspecting the sheet which is conveyed by the first and second suction conveyance units 1 and 2 are adopted, it becomes possible to sufficiently exhibit the high reading accuracy that the CIS originally has. The camera and CIS will be described later.

As illustrated in FIG. 2, in an inspection object conveyance direction which directs from left to right in the drawing, the conveyance unit which is located on the upstream side is the first suction conveyance unit 1 and the conveyance unit which is located on the downstream side is the second suction conveyance unit 2. Although the first suction conveyance unit 1 and the second suction conveyance unit 2 have the same functional configuration, the first suction conveyance unit 1 is arranged horizontally in such a manner that the conveyance surface onto which the inspection object is sucked and conveyed is located on the upper surface side. Accordingly, the inspection object which is conveyed by the first suction conveyance unit 1 is conveyed with its front surface facing upward. On the other hand, the second suction conveyance unit 2 is arranged in a state of being turned upside down relative to the first suction conveyance unit 1. That is, the second suction conveyance unit 2 is horizontally arranged in such a manner that the conveyance surface onto which the inspection object is sucked and conveyed is located on the lower surface side. Accordingly, the inspection object which is conveyed by the second suction conveyance unit 2 is conveyed with its back surface facing downward. The first suction conveyance unit 1 and the second suction conveyance unit 2 are arranged adjacent to each other in such a manner that the respective conveyance surfaces almost match each other and are able to continuously convey the inspection object along one horizontal conveyance path.

As illustrated in FIG. 2, the image inspection device 200 has two inspection sections (a first inspection section 11 and a second inspection section 12) as elements for inspecting images on the inspection object. The first inspection section 11 is installed above an upstream-side end of the first suction conveyance unit 1 in a state of being directed downward so as to face the conveyor belt 6. The second inspection section 12 is installed under an upstream-side end of the second suction conveyance unit 2 in a state of being directed upward so as to face the conveyor belt 6. The first inspection section 11 and the second inspection section 12 are configured by the CISs (Contact Image Sensor) which are the same as each other in specification. However, sensors which are based on other principles or have other structures and configurations are not limited to the CISs as the inspection sections which read out images which are formed on the inspection object for inspection, and cameras may also be used as will be described later.

As illustrated in FIG. 2, the image inspection device 200 includes an introduction guide plate 13 which is adjacent to the upstream-side end of the first suction conveyance unit 1 and guides the inspection object which is sent from the upstream-side printing device 100 to the conveyance surface.

In addition, a press roller 14 which presses floating of a top edge of the inspection object which is introduced by being guided by the introduction guide plate 13 is installed above the driven roller 4 of the first suction conveyance unit 1. The press roller 14 rotates following the conveyor belt 6.

As illustrated in FIG. 2, the image inspection device 200 includes an intermediate guide plate 15 which is installed between the first suction conveyance unit 1 and the second suction conveyance unit 2 and guides the inspection object sent from the first suction conveyance unit 1 to the conveyance surface of the second suction conveyance unit 2. In addition, a hanging prevention roller 16 is installed under the driven roller 4 of the second suction conveyance unit 2 as a hanging prevention member which prevents the top edge of the inspection object which is introduced by being guided by the intermediate guide plate 15 from hanging as will be described later with reference to other drawings (see, for example, FIG. 6 and FIG. 8).

As illustrated in FIG. 2, the image inspection device 200 includes a discharge guide plate 17 which is adjacent to a downstream-side end of the second suction conveyance unit 2 and discharges the inspection object which is conveyed by the second suction conveyance unit 2.

Next, a basic configuration of the image inspection device 200 which is not illustrated in FIG. 2 will be described with reference to FIG. 3. The aforementioned first inspection section 11 and second inspection section 12 are respectively attached to a first support section 21 and a second support section 22 which are positioned relative to the first suction conveyance unit 1 and the second suction conveyance unit 2 respectively. Although the first support section 21 and the second support section 22 have substantially the same functional configuration, the first support section 21 and the second support section 22 are arranged in a state of being mutually turned upside down so as to face the respective conveyance surfaces of the first suction conveyance unit 1 and the second suction conveyance unit 2 which are arranged in a state of being mutually turned upside down. In addition, as will be described later with reference to other drawings (see, for example, FIG. 5 and so forth), the first support section 21 and the second support section 22 are supported to a frame (not illustrated) of the image inspection device 200 to be rotationally movable around support points A and B respectively at both ends of a long support shaft 23. In FIG. 3, a central axis of the long support shaft 23 is vertical to a surface of paper and the first support section 21 and the second support section 22 are supported to the frame in a state of being rotationally movable in both left and right directions around this central axis (described later with reference to arrows indicated in FIG. 5). In addition, the first support section 21 and the second support section 22 are supported to the frame (not illustrated) of the image inspection device 200 to be rotationally movable around a support point C by a short support shaft 24 respectively. In FIG. 3, a central axis of the short support shaft 24 is parallel with the surface of paper and almost horizontal and the first support section 21 and the second support section 22 are supported to the frame in a state of being rotationally movable around the central axis of the short support shaft 24 in both paper surface forward direction and paper surface rearward direction (described later with reference to the arrows indicated in FIG. 5). Although details will be described later, supported states of the first support section 21 and the second support section 22 at the support points A, B and C are not fixed and the image inspection device 200 is configured that even in a case where the frame is deformed by addition of external force, the first support section 21 and the second support section 22 are not deformed and no harmful change occurs in an arrangement relation of the both because the first support section 21 and the second support section 22 are made rotationally movable in the abovementioned two directions.

According to the image inspection device 200 in the embodiment having the above-described basic configuration, the inspection object is stably conveyed in a state of being sucked and held on the conveyance surface which is located on the upper surface side of the first suction conveyance unit 1 and then is delivered to the second suction conveyance unit 2 and is stably conveyed in a state of being sucked and held on the conveyance surface which is located on the lower surface side of the second suction conveyance unit 2. Since the inspection object is conveyed in a sucked state in this way, the position and the posture of the inspection object do not become unstable while the inspection object is being conveyed and thereby it becomes possible to inspect the images on both the front and back surfaces of the inspection object with necessary accuracy by the two inspection sections 11 and 12 while stably conveying the inspection object in one direction without using a complicated mechanism which inverts the inspection object.

In addition, according to the image inspection device 200, since the respective inspection sections 11 and 12 are arranged in the vicinity of the upstream-side ends of the respective suction conveyance units 1 and 2, most parts of the conveyance surfaces of the respective suction conveyance units 1 and 2 are in open states and there is no obstacle on the conveyance surfaces. Therefore, a manager who manages the image inspection device 200 or a worker who performs maintenance and so forth of the image inspection device 200 is able to access to the conveyance surfaces of the respective suction conveyance units 1 and 2 with ease. Accordingly, since the conveyance path 102 of the inspection object is not sandwiched between the inspection sections unlike the camera unit of the image forming apparatus which is disclosed in Patent Literature 1 which is described in (Background Art), even when a jam occurs in the inspection object which is being conveyed, the manager or the worker is able to remove the jammed inspection object by inserting his/her hand into a trouble-occurred place with ease.

In addition, according to the image inspection device 200, since the respective inspection sections 11 and 12 are arranged in the vicinity of the upstream-side ends of the respective suction conveyance units 1 and 2, in a case where results of image detection by the inspection sections 11 and 12 are utilized on the downstream side, it is preferable to arrange the inspection sections in the vicinity of the upstream side ends of the suction conveyance units because sufficient time is secured. For example, in a case where an inspection object which is decided to be unfavorable in inspection result is sorted as a defective product in the post-processing device 300 which is located at the rear stage of the image inspection device 200, it is desirable to obtain information from the inspection sections 11 and 12 as soon as possible for decision of whether the inspection object is the defective product. According to the image inspection device 200 of the present embodiment, since the inspection sections 11 and 12 are installed on the upstream sides of the first and second suction conveyance units 1 and 2 respectively, it becomes possible for a control unit to obtain the inspection results earlier than a case where the inspection sections are installed on the downstream sides and to execute the necessary post-processing without delay.

<<Details of Structure of Image Inspection Device>>

Next, a concrete structure of the image inspection device 200 which has the above-described basic structure described with reference to FIG. 4 to FIG. 12. First, the first support section 21 and the second support section 22 to which the first inspection section 11 and the second inspection section 12 are attached respectively and a structure and so forth that the respective first and second support sections 21 and 22 are positioned relative to the first and second suction conveyance units 1 and 2 respectively will be described with reference to FIG. 4 to FIG. 9.

As illustrated particularly in FIG. 5 and FIG. 9, the first support section 21 is a frame body having an almost square outer shape which almost matches a planar shape of the first suction conveyance unit 1. In four walls of the first support section 21, the first inspection section 11 which sets a direction (a width direction of the inspection object) orthogonal to the inspection object conveyance direction as a longitudinal direction is attached to the inner side of an upstream-side wall which is orthogonal to the inspection object conveyance direction. An inspection element of the first inspection section 11 is directed to a direction of the conveyor belt 6.

As illustrated particularly in FIG. 9, support legs 25 which are set to predetermined dimensions are formed on four corners of the first support section 21 so as to project toward the side which faces the first suction conveyance unit 1. A groove 26 is vertically formed in each support leg 25. As illustrated particularly in FIG. 4 and FIG. 5, the four support legs 25 of the first support section 21 abut on the upper surface of the platen 8 which protrudes from the intermediate plate 7 of the first suction conveyance unit 1 at every two positions (four positions in total) with the conveyor belt 6 being sandwiched therebetween. Then, the first support section 21 holds the first suction conveyance unit 1 by pressing the first suction conveyance unit 1 against the support legs 25 and thereby maintains a distance between the first inspection section 11 and the conveyance surface of the first suction conveyance unit 1 constant as will be described in the following and as indicated by a distance D particularly in FIG. 4.

As illustrated particularly in FIG. 4, FIG. 5 and FIG. 7, first, a winding shaft 27 is installed on one wall of the first support section 21 which is parallel with the inspection object conveyance direction on the opposite side of the first suction conveyance unit 1 in parallel with the inspection object conveyance direction. As illustrated particularly in FIG. 5 and FIG. 7, every two pulleys 28 a and 28 b are installed on both ends of the winding shaft 27. In addition, pulleys 29 and 29 are installed respectively on two corners of the other wall of the first support section 21 which is parallel with the inspection object conveyance direction on the opposite side of the first suction conveyance unit 1. A suspension wire 30 is wound around the pulleys 28 a and 28 b of the winding shaft 27 with its base end being coupled thereto. Two suspension wires 30 and 30 of the outer two pulleys 28 a and 28 a in every two pulleys on the both ends of the winding shaft 27 are led out in a direction which is orthogonal to the inspection object conveyance direction, are wound around the two pulleys 29 and 29 which are located on the opposite side of the winding shaft 27 respectively, are guided to the lower side first suction conveyance unit 1 along the two grooves 26 and 26 which are formed in the two support legs 25 and 25 and are coupled to two places of the platen 8 on which the two support legs 25 and 25 abut at respective leading ends thereof. In addition, the two suspension wires 30 and 30 of the inner two pulleys 28 b and 28 b in the every two pulleys on the both ends of the winding shaft 27 are guided downward along the two grooves 26 and 26 which are formed in the two support legs 25 and 25 which are located directly under the wires 30 and 30 and are coupled to two places of the platen 8 on which the two support legs 25 and 25 abut at respective leading ends thereof.

A handle 31 which is rotationally movable through 360 degrees is installed on the wall of the first support section 21 which is opposite to the wall on which the winding shaft 27 is installed with the conveyor belt 6 being sandwiched. Although details are not illustrated, a rotary shaft of the handle 31 is coupled to the winding shaft 27 in linkage with the winding shaft 27 via a transmission mechanism such as a belt, a pulley, a worm, a wheel and so forth. Accordingly, it becomes possible to wind the suspension wires 30 on the pulleys 28 a and 28 b, to lift the platen 8, to press the platen 8 against the leading ends of the four support legs 25 of the first support section 21 with necessary force and thereby to position the platen 8 by rotationally moving the winding shaft 27 in a predetermined direction by operating the handle 31. Here, since each suspension wire 30 is arranged in the groove 26 of each support leg 25 and is coupled to the platen 8, force that the suspension wire lifts the platen 8 directly works on a position on which each support leg 25 abuts. Accordingly, an action of fixing the platen 8 (that is, the first suction conveyance unit 1) onto the support legs 25 becomes sure. Incidentally, although force which is necessary to lift the first suction conveyance unit 1 with the suspension wire 30 depends on weight and so forth of each component, the force may be set to, for example, 7N for every suspension wire 30, that is, to 28N in total for the four suspension wires 30.

The first support section 21 on which the first inspection section 11 is loaded positions the platen 8 so as to match a virtual plane which is defined by the leading ends of the four support legs 25 and fixes the platen 8 at a position concerned with the necessary force in this way. Accordingly, the first inspection section 11 which is attached to a predetermined position of the first support section 21 becomes parallel with the inspection object conveyance surface which faces the first inspection section 11 and a distance between the first inspection section 11 and the conveyance surface reaches a fixed value which is determined in advance. In addition, even when the platen 8 is not in its original flattened surface form and there are some problems in flatness, it is also possible to correct the flatness of the platen 8 with the aid of force which works to pull the platen 8 with the suspension wires 30 and to bring the platen 8 into abutment on the support legs 25.

Although description is made on the assumption that the inspection sections 11 and 12 of the present embodiment are configured by the CISs, in general, the CIS is shallow in depth of field and a high arrangement accuracy is required for obtaining an expected reading accuracy. For example, tolerance when setting to a distance of about 12 mm is about ±0.2 mm. Accordingly, the high accuracy becomes necessary for positioning of the CISs and the inspection object conveyance surface. However, according to the present embodiment, the first inspection section 11 is attached to the first support section 21 so as to be parallel with the virtual plane which is configured by respective leading end faces of the four support legs 25 which are formed on the first support section 21 and the platen 8 is fixed in the virtual plane by abutting the respective support legs 25 of the first support section 21 on the platen 8. Thereby, the platen 8 becomes parallel with the first inspection section 11 and it becomes possible to properly inspect the images on the inspection object which is conveyed by the first suction conveyance unit 1 with expected accuracy by the first inspection section 11.

Although the first support section 21 and the first suction conveyance unit 1 are described above as the mechanism which performs positioning by pulling the first and second suction conveyance units 1 and 2 with the suspension wires 30 into abutment on the support legs 25 of the first and second support sections 21 and 22 respectively, the second support section 22 and the second suction conveyance unit 2 are configured as the mechanism which is almost the same as that of the first support section 21 and the first suction conveyance unit 1 functionally, and therefore the description thereof is omitted by quoting the description of the first support section 21 and so forth. However, as illustrated on the right side in FIG. 5, the direction of the force and so forth of the second support section 22 is different from that of the first support section 21 and so forth in that in the second support section 22, the second suction conveyance unit 2 which is located above the second support section 22 is pulled downward with the four suspension wires 30 into abutment on the upper end faces of the upward protruding four support legs 25 as illustrated on the right side in FIG. 5. Incidentally, the first and second support sections 21 and 22 of the present embodiment are configured to position the platen 8 so as to match the virtual plane which is defined by the leading ends of the four support legs 25. However, it is sufficient that the virtual plane be uniquely determined by the leading ends of the support legs 25 and therefore three or more support legs 25 may be formed. In addition, the positioning accuracy of the platen 8 may be further increased by forming five or more support legs 25.

As illustrated particularly in FIG. 4 to FIG. 7, in the first support section 21, the long support shaft 23 which is orthogonal to the inspection object conveyance direction is bridged on the upstream aides of one pair of walls of the first support section 21 which is parallel with the inspection object conveyance direction. Both ends of the long support shaft 23 project to the outside of the walls and the long support shaft 23 is coupled to the frame (not illustrated) of the image inspection device 200 to be rotationally movable as indicated by a bidirectional arrow around the long support shaft 23 in FIG. 5. That is, the first support section 21 is attached to be rotationally movable in an orientation that the downstream side or the upstream side of the conveyor belt 6 vertically swings around the long support shaft 23. In addition, in the first support section 21, a lower end of a coupling plate 32 which extends upward is fixed to downstream-side central parts of one pair of walls of the first support section 21 which is orthogonal to the inspection object conveyance direction. An upper end of the coupling plate 32 is coupled to the frame (not illustrated) of the image inspection device 200 to be rotationally movable by the short support shaft 24 which is parallel with the inspection object conveyance direction. A central axis of the short support shaft 24 is orthogonal to a central axis of the long support shaft 23 and is almost horizontal. The first support section 21 is supported on the frame in a state of being rotationally movable in both diagonally forward direction and diagonally rearward direction of the paper sheet around the short support shaft 24 as indicated by a bidirectional arrow around the short support shaft 24 in FIG. 5. Accordingly, the both ends of the long support shaft 23 serve as the support points A and B (see FIG. 3) which support the first support section 21 on the frame to be rotationally movable and the short support shaft 24 serves as the support point C (see FIG. 3) which supports the first support section 21 on the frame to be rotationally movable. Since the second support section 22 has the structure which is almost the same as the structure of the first support section 21 in function and is attached to the frame in the same way, description thereof is omitted by quoting the description of the first support section 21 and so forth. A state where the first support section 21 is supported at the support points A, B and C is not fixed in this way. Therefore, in a case where certain external force is applied to the frame and thereby the frame is deformed, since the first support section 21 is in a state of being supported to be rotationally movable in two orthogonal planes which are illustrated in FIG. 5 respectively, the posture is maintained as soon as possible by releasing the force which is transmitted from the frame so as to avoid deformation of the first support section 21 and occurrence of a change which is harmful to its arrangement relation with the second support section 22.

As described above, in the present embodiment, the first and second support sections 21 and 22 which load the first and section inspection sections 11 and 12 respectively are supported at the three points A, B, and C in a state of not being fixed, that is, being rotationally movable relative to the frame of the image inspection device 200. Thus, the following effects are obtained owing to the abovementioned structure. That is, in a case where the image inspection device 200 is installed on a floor which is low in flatness and in a case where although heights of the four support legs 25 of the image inspection device 200 are adjusted by an adjustor so as to cope with installation of the image inspection device 200 on the floor which is low in flatness, height adjustment is not performed perfectly and thereby a difference occurs among the heights of the support legs 25, the image inspection device 200 shifts to an inclined posture which deviates from a necessary horizontal state in either case. Therefore, the external force is applied to the frame of the image inspection device 200 and distortion occurs. When the distortion occurs in the frame, in a case where the first and second support sections 21 and 22 are directly fixed to the frame, firstly, the distortion also occurs in the first and second support sections 21 and 22 and a positional relation between each of the first and second inspection sections 11 and 12 which are attached to the first and second support sections 21 and 22 respectively and the inspection object conveyance surface changes. In addition, secondarily, also a mutual positional relation between the first inspection section 11 and the second inspection section 12 changes. As a result, a trouble that the first and second inspection sections 11 and 12 erroneously detect the images on the inspection object occurs.

However, according to the present embodiment, the first and second support sections 21 and 22 which load the first and second inspection sections 11 and 12 respectively are supported on the frame of the image inspection device 200 at the three points A, B, and C in a non-fixed state. Therefore, even in a case where useless external force is applied to the frame of the image inspection device 200 and the distortion occurs in the frame, the distortion is difficult to transmit to the first and second support section 21 and 22, the regular positional relation between each of the first and second inspection sections 11 and 12 which are attached to the first and second support sections 21 and 22 respectively and each of the first and second suction conveyance units 1 and 2 is maintained, and a change is difficult to occur in the properly set mutual positional relation between the first inspection section 11 and second inspection section 12. Consequently, a trouble that the first and second inspection sections 11 and 12 erroneously detect the images on the inspection object does not occur.

As illustrated particularly in FIG. 6 and FIG. 8, the hanging prevention roller 16 is installed at a position which corresponds to a part under the driven roller 4 of the second suction conveyance unit 2, that is, the position which is located under the upstream-side end of the second suction conveyance unit 2. As described before with reference to FIG. 2, the hanging prevention roller 16 is the hanging prevention member which prevents the top edge of the inspection object which is introduced via the intermediate guide plate 15 from hanging downward. The hanging prevention roller 16 has a roller portion which is divided into a pectinate shape in an axial direction which is orthogonal to the inspection object conveyance direction. When the inspection object is sent from the upstream first suction conveyance unit 1 into the second suction conveyance unit 2, the top edge of the inspection object abuts on the hanging prevention roller 16 and runs on the hanging prevention roller 16 before the top edge of the inspection object hangs down under its own weight or because of downward curling, and then the inspection object is sandwiched between the conveyor belt 6 and the hanging prevention roller 16 and suction conveyance of the inspection object by the second suction conveyance unit 2 is started. Alternatively, before the top edge of the inspection object hangs down, the top edge is sandwiched between the hanging prevention roller 16 and the conveyor belt 6 and the suction conveyance of the inspection object by the second suction conveyance unit 2 is started.

As described above, in the present embodiment, the hanging prevention roller 16 is installed at an inspection object delivering position between the first suction conveyance unit 1 and the second suction conveyance unit 2. Owing to the abovementioned structure, the following effects are obtained. That is, in the image inspection device 200 according to the present embodiment, the first inspection section 11 reads the image on the upper surface of the inspection object at the entrance of the first suction conveyance unit 1 and a timing that the second inspection section 12 starts reading the image on the lower surface of the inspection object is set from a timing that the first inspection section 11 performs image reading and a later conveyance length. Propriety is decided by collating the images which are detected by the CISs which configure the first and second inspection sections 11 and 12 with original image data and a definition of the images which are detected by the CISs is as high as about 300 dpi to about 600 dpi. Therefore, in a case where the top edge of the inspection object hangs down when the inspection object is delivered between the first suction conveyance unit 1 and the second suction conveyance unit 2, a time lag occurs in a timing that the inspection object enters the second suction conveyance unit 2 and erroneous image detection occurs when reading the images on the inspection object by the second inspection section 12. However, according to the present embodiment, since the hanging prevention roller 16 is installed at the entrance of the second suction conveyance unit 2, the trouble that the top edge of the inspection object hangs down under its own weight does not occur, no time lag occurs in timing of image reading by the second inspection section 12 which is set on the basis of the reading timing and so forth by the first inspection section 11, and the trouble of erroneous detection does not occur.

In addition, in a case when the top edge of the inspection object is seen along a line of sight which is parallel with the conveyance direction, there are cases where wavy deformation (cockling) is observed. Since occurrence of such deformation leads to a reduction in accuracy of inspection by the inspection section such as the CIS and so forth and induces the erroneous detection, it is preferable to correct the deformation to the greatest possible extent. In the present embodiment, since the hanging prevention roller 16 sandwiches the inspection object between its pectinate roller portion and the conveyor belt 6, cockling of the inspection object is corrected in shape in a direction that a crest of cockling is leveled and a depth of a trough is reduced and consequently the deformation is changed to a wavy form which is smaller in cycle, the result which is the same as the result of cockling correction is attained and an effect of preventing erroneous detection of the images by the first and second inspection sections 11 and 12 is obtained.

As illustrated particularly in FIG. 9 to FIG. 12, the first support section 21 is equipped with a first conveyance direction adjustment element which adjusts the direction that the inspection object is conveyed by the first suction conveyance unit 1. In the first support section 21, a fixing pin 35 is installed on one of walls making a pair which is parallel with the inspection object conveyance direction in a state of projecting downward. The fixing pin 35 is inserted into a positioning hole 36 which is formed in the platen 8. In addition, a movable pin 37 is installed on the other of the walls making the pair which is parallel with the inspection object conveyance direction in a state of projecting downward. The movable pin 37 is eccentrically attached to a lower surface of a cylindrical operation member 38 which is attached to the first support section 21 to be rotationally movable and is inserted into a slot 39 which is formed in the platen 8. An operation handle 40 which rotationally moves the operation member 38 is installed on a circumferential surface of the operation member 38. A scale plate 41 which indicates an angle through which the operation member 38 rotationally moves is attached around the operation member 38.

In a case where the first suction conveyance unit 1 is pulled up from a state which is illustrated in FIG. 10 with the suspension wires 30 (not illustrated in FIG. 10) and is brought into abutment on the four support legs 25 of the first support section 21, the fixing pin 35 is inserted into the positioning hole 36, the movable pin 37 is inserted into the slot 39 and thereby the first suction conveyance unit 1 shifts to a state illustrated in FIG. 7. This state corresponds to the state which is illustrated in FIG. 5 as a whole including the second suction conveyance unit 2 and the second inspection section 12 and indicates a state in ordinary use. In a case of occurrence of a trouble in inspection accuracy of the first inspection section 11 and so forth caused by insufficient flatness of the first inspection section 11 and the first suction conveyance unit 1 under such ordinary use, it becomes necessary to correct the direction that the inspection object is conveyed by the first suction conveyance unit 1.

In a case where the direction that the inspection object is conveyed by the first suction conveyance unit 1 is corrected by using the first conveyance direction adjustment element, first, the force of the suspension wires 30 to pull up the first suction conveyance unit 1 is properly reduced to shift to a state where the platen 8 is slidable relative to the support legs 25. Then, as illustrated in FIG. 11 and FIG. 12, the operation member 38 is rotated by a necessary angle by the operation handle 40 and the movable pin 37 is turned by a necessary amount. It is possible to read a fluctuation of the angle according to an operation amount of the operation handle 40 from the scale plate 41. It is possible to adjust the orientation of the platen 8 of the first suction conveyance unit 1 by a maximum angle 9 around the fixing pin 35 by performing such operations as described above. After adjustment, the force of pulling-up by the suspension wires 30 is properly increased thereby to fix the platen 8 to the support legs 25.

As described above, in the present embodiment, the mechanism which adjusts the orientations of the first and second suction conveyance units 1 and 2 relative to the first and second support sections 21 and 22 which load the first and second inspection sections 11 and 12 respectively and thereby changes the inspection object conveyance direction is installed. Therefore, in a case where a trouble occurs in the positional relation between each of the first and second inspection sections 11 and 12 and the inspection object conveyance direction for some reasons, it is possible to correct the positional relation between each of the inspection sections 11 and 12 and the inspection object conveyance direction by operating the operation handle 40 and thereby to prevent occurrence of the erroneous detection. In addition, in a case where skewing of the inspection object occurs on the first suction conveyance unit 1, a timing that the top edge of the inspection object reaches the hanging prevention roller 16 is delayed when delivering the inspection object to the second suction conveyance unit 2 and thereby there is the possibility that the effect of preventing hanging by the aforementioned hanging prevention roller 16 may be reduced. However, it becomes possible to surely secure the effect of hanging prevention by the aforementioned hanging prevention roller 16 by adjusting the inspection object conveyance direction of the upstream side first suction conveyance unit 1 by operating the operation handle 40 so as to correct skewing of the inspection object and making the respective conveyance directions of the first suction conveyance unit 1 and the second suction conveyance unit 2 match each other.

Incidentally, a second conveyance direction adjustment element which adjusts the direction that the inspection object is conveyed by the second suction conveyance unit 2 is installed also on the second support section 22 similarly to the first support section 21. However, the configuration of the second conveyance direction adjustment element is the same as the structure of the first conveyance direction adjustment element in function and therefore repetitive description is avoided by quoting the description of the first conveyance direction adjustment element.

Modified Examples of Image Inspection Device According to Embodiment

Modified examples of the image inspection device 200 according to the embodiment of the present invention will be described with reference to FIG. 13 to FIG. 18.

FIG. 13 is a schematic front view illustrating a first modified example of the image inspection device 200. Although an image inspection device 200 a according to a first modified example is the same as the image inspection device 200 according to the embodiment in that the first suction conveyance unit 1 and the second suction conveyance unit 2 are arranged on the upstream side and the downstream side respectively along the inspection object conveyance direction, the conveyance surface of the second suction conveyance unit 2 has an angle which is inclined downward toward the downstream side relative to the conveyance surface of the first suction conveyance unit 1.

Although, in the embodiment, the respective conveyance directions of the first suction conveyance unit 1 and the second suction conveyance unit 2 match each other, in such a configuration, there are cases where the top edge of the inspection object which is delivered to the second suction conveyance unit 2 hangs down and therefore the inspection object is not sucked onto the second suction conveyance unit 2 properly and delivery of the inspection object is not smoothly performed. In such a case, the downstream-side end of the second suction conveyance unit 2 is lowered slightly downward so as to make the above-described inclined angle as in the first modified example. For setting the inclined angle, it is possible to adjust the inclined angle by reducing tension of the suspension wire 30 which suspends the second suction conveyance unit 2 on the downstream side in comparison with the tension on the upstream side.

A specific example of the inclined angle will be described. For example, paper and so forth of a thickness which is at least about 200 g/cm² in weighting is strong in tensility and therefore this paper is difficult to hang down when delivered. Therefore, it is preferable to set an angle between the conveyance surface of the first suction conveyance unit 1 and the conveyance surface of the second suction conveyance unit 2 to about 177 degrees which is not more than 180 degrees in the angle which is measured under both the first and second suction conveyance units 1 and 2. That is, in this case, an angle by which the downstream-side end of the second suction conveyance unit 2 is lowered is about three degrees. For example, in a case of thin paper which is about 40 g/cm² in weighting, since the thin paper is weak in tensility and is easy to hang down when delivered. Therefore, it is preferable to set the angle between the conveyance surface of the first suction conveyance unit 1 and the conveyance surface of the second suction conveyance unit 2 to about 170 degrees in the angle which is measured under both the suction conveyance units 1 and 2. That is, an angle by which the downstream-side end of the second suction conveyance unit 2 is lowered is about 10 degrees. According to knowledge which is based on two examples that the inventors of the present invention have learned in this way, although it is preferable to set the inclined angle of the conveyance surface of the second suction conveyance unit 2 which is measured under both the suction conveyance units 1 and 2 in a range from about 180 degrees to about 170 degrees, there may be cases where a favorable angle range is increased from 170 degrees by further several degrees under conditions which are different from those of the above-described two examples.

According to the image inspection device 200 a, even in a case where the top edge of the inspection object which is conveyed from the first suction conveyance unit 1 to the second suction conveyance unit 2 hangs down from the conveyance surface of the first suction conveyance unit 1 downward due to the paper quality and so forth, the inspection object is pressed against the conveyance surface of the second suction conveyance unit 2 which is inclined downward toward the downstream side and therefore the inspection object is surely sucked and held on the conveyance surface and is stably conveyed toward the downstream side.

In addition, in the image inspection device 200 a, the angle which is inclined downward toward the downstream side of the conveyance surface of the second suction conveyance unit 2 may be set in accordance with image formation conditions when forming the images on the inspection object. Here, as the image formation conditions, an orientation of the inspection object, a printing amount, arrangement balance of a printing range in an image forming surface on the inspection object and so forth may be given by way of example in addition to the kind of the inspection object which is expressed by the above-described weighting. The aforementioned inclined angle may also be set to a proper value manually or automatically in accordance with these image formation conditions.

FIG. 14 is a schematic front view illustrating a second modified example.

In an image inspection device 200 b according to the second modified example, the conveyance surface of the downstream-side end of the first suction conveyance unit 1 and the conveyance surface of the upstream-side end of the second suction conveyance unit 2 are mutually superimposed. Other configurations are the same as the configurations of the image inspection device 200 according to the embodiment. On a part where the two conveyance surfaces are mutually superimposed, the two conveyor belts 6 and 6 face each other leaving a space of not more than about 0.5 mm in a vertical direction. As one example, since there are many cases where a thickness of paper on which images are formed by the image forming apparatus is about 0.2 mm in a case of thick paper, in such a case, when a space between the two conveyor belts 6 and 6 is not more than about 0.5 mm, there is no trouble in delivery of the inspection object. According to the second modified example, there are effects that it is not necessary to install a mechanism (for example, the intermediate guide plate 15 illustrated in FIG. 2) used for delivery of the inspection object between the upstream-side first suction conveyance unit 1 and the downstream-side second suction conveyance unit 2 and delivery is performed smoothly.

FIG. 15 is a schematic front view illustrating a third modified example.

In an image inspection device 200 c according to the third modified example, cameras 11 a and 12 a and CISs 11 b and 12 b are installed on the first suction conveyance unit 1 and the second suction conveyance unit 2 respectively as the inspection sections. In both of the first and second suction conveyance units 1 and 2, the CISs 11 b and 12 b which are relatively high in required arrangement accuracy (shallow in depth of field) are arranged relatively on the downstream side of the inspection object conveyance direction, and the cameras 11 a and 12 a which are relatively low in required arrangement accuracy (deep in depth of field) are arranged relatively on the upstream side of the inspection object conveyance direction. Other configurations are the same as the configurations of the image inspection device 200 according to the embodiment. In the first and second suction conveyance units 1 and 2, the force of sucking the inspection object which is being conveyed is higher in a state where the inspection object is sucked onto a part which reaches the downstream side of the conveyor belt 6 and is conveyed with most of the holes closed than in a state where the inspection object is sucked only onto an upstream side part of the conveyor belt 6 and is conveyed with most of the holes not closed. That is, in a case where cockling and curling are observed on the paper, the paper is difficult to closely adhere to the conveyor belt 6 in the former state and the paper is easy to closely adhere to the conveyor belt 6 in the latter case. Therefore, it becomes possible to arrange different kinds of inspection sections 11 and 12 with arrangement accuracies which are necessary for making the inspection sections 11 and 12 function with respective inspection accuracies and to secure the levels of the inspection accuracies of the respective inspection sections 11 and 12 by arranging the cameras 11 a and 12 a which are relatively low in accuracy (deep in depth of field) and the CISs 11 b and 12 b which are relatively high in accuracy (shallow in depth of field) on the respective first and second suction conveyance units 1 and 2 as described above.

FIG. 16 is a schematic front view illustrating a fourth modified example.

An image inspection device 200 d according to the fourth modified example has a hanging prevention member 42 which is formed by extending a plate body which is located under the intermediate guide plate 15 up to a part under the upstream-side end of the second suction conveyance unit 2 between the first suction conveyance unit 1 and the second suction conveyance unit 2. Other configurations are the same as the configurations of the image inspection device 200 according to the embodiment. Owing to arrangement of the hanging prevention member 42, the effect of preventing the top edge of the inspection object which is delivered from the first suction conveyance unit 1 to the second suction conveyance unit 2 from hanging down under its own weight and due to occurrence of curling and so forth is obtained as in the case of the aforementioned hanging prevention roller 16 (see FIG. 2, FIG. 6 and so forth).

FIG. 17 is a schematic front view illustrating a fifth modified example.

In an image inspection device 200 e according to the fifth modified example, a skew correction roller 43 which corrects skewing of the inspection object which is sent from the upstream side of the first suction conveyance unit 1 is installed adjacent to the upstream side of the first suction conveyance unit 1. The skew correction roller 43 is put on standby in a stopped state and starts rotating in the inspection object conveyance direction when the inspection object (the printing paper) abuts on the roller 43. A top edge sensor 44 (see FIG. 4 and FIG. 5) which detects the top edge of the inspection object is installed right next to the upstream side of the skew correction roller 43. When the top edge sensor 44 detects the top edge of the inspection object, the control unit which receives a detection signal from the top edge sensor 44 drives the skew correction roller 43. Other configurations are the same as the configurations of the image inspection device 200 according to the embodiment. Owing to installation of the skew correction roller 43, even in a case where skewing occurs on the printing paper (the inspection object) which is sent from the upstream-side printing device 100, it becomes possible to correct skewing of the printing paper and to send the printing paper to the first inspection section 11 in a proper posture.

FIG. 18 is a schematic front view illustrating a sixth modified example.

In an image inspection device 200 f according to the sixth modified example, the CISs 11 b and 12 b are installed on the first suction conveyance unit 1 and the second suction conveyance unit 2 respectively as the inspection sections. The CISs 11 b and 12 b as the inspection sections are arranged in the vicinity of the downstream-side ends of both the first suction conveyance unit 1 and the second suction conveyance unit 2. Other configurations are the same as the configurations of the image inspection device 200 according to the embodiment. In the first and second suction conveyance units 1 and 2, the force of sucking the inspection object which is conveyed is higher in a state where the inspection object is sucked onto the part which reaches the downstream side of the conveyor belt 6 and is conveyed with most of the holes closed than in a state where the inspection object is sucked only onto the upstream side part the conveyor belt 6 and is conveyed with most of the holes not closed. That is, in the first and second suction conveyance units 1 and 2, as conveyance is promoted toward the downstream side, force that the inspection object which is conveyed is held by the conveyor belt 6 is increased further and holding is stabilized further. Therefore, in view of a fact that the CISs 11 b and 12 as the inspection sections are high in arrangement accuracy which is necessary for making the CISs 11 b and 12 b function with expected inspection accuracy, the CIDs 11 b and 12 b are arranged on the downstream sides of the respective first and second suction conveyance units 1 and 2 as described above. Thereby, the inspection object which is conveyed by the first and second suction conveyance units 1 and 2 down to the downstream side is stably held on the conveyor belt 6 with the aid of sufficient suction force, and it becomes possible to detect the images on the inspection object by the CISs 11 b and 12 b with expected high accuracy.

In a case where the top edge of the inspection object is located on the upstream side of the conveyor belt 6 and suction force of a negative pressure and so forth is low, since a rear edge of the inspection object has not yet entered the first suction conveyance unit 1, suction bonding is not performed and the first suction conveyance unit 1 is in a state which is unstable in conveyance of the inspection object. However, when the top edge of the inspection object reaches the rear end of the first suction conveyance unit 1, the entire inspection object is sucked and bonded onto the conveyance surface, conveyance of the inspection object is stabilized, and the possibility that the inspection object may flutter in a height direction is reduced. Then, when the rear edge of the inspection object reaches the first inspection section 11 b which is located on the downstream side of the first suction conveyance unit 1, for example, the negative pressure which works on the rear edge of the inspection object becomes lower. However, the top edge of the inspection object is sucked onto the conveyance surface of the downstream-side second suction conveyance unit 2, and even when the negative pressure is lowered only on the rear edge of the inspection object, it becomes possible to maintain a stable conveyance state with the aid of inertia of a state where stable conveyance is performed in a state where the negative pressure is high until just before reaching here. However, it is possible to maintain the stable state only with the aid of the above-described inertia.

Incidentally, when the inspection object enters the suction conveyance unit concerned, the rear edge side of the inspection object which has not yet entered the suction conveyance unit concerned irregularly moves with ease because movement in a direction other than the conveyance direction is not restricted. On the other hand, since the top edge side of the inspection object which has entered the suction conveyance unit concerned is pressed against the conveyor belt 6 of the suction conveyance unit concerned by the press roller 14 and is sucked and bonded onto the conveyor belt 6, the top edge side of the inspection object is difficult to move. When conveyance is further promoted, an area of the inspection object which is sucked and bonded onto the conveyor belt 6 by suction is gradually increased and conveyance stability is increased further. Then, when the inspection object is discharged from the suction conveyance unit concerned, most of the area of the inspection object is sucked and bonded onto the conveyor belt 6 and therefore the inspection object is conveyed in a sufficiently stable state. A state where the inspection object is sucked and bonded onto the conveyor belt 6 is more and more stabilized as the inspection object is conveyed in this way. A state where the stability in conveyance is further maintained is described using the term “inertia” or described in the expression using the term “inertia” as described above in the present specification.

FIG. 19 is a perspective front view illustrating a seventh modified example.

An image inspection device 200 g according to the seventh modified example includes the first suction conveyance unit 1 and the second conveyance unit 2. Only the upstream-side first suction conveyance unit 1 is illustrated in FIG. 19 along a line of sight seeing downward diagonally from above diagonally on the downstream side of the front view, and illustration of the downstream-side second suction conveyance unit 2 is omitted. In addition, in the configuration of the first suction conveyance unit 1, illustration of some structures is changed or omitted in FIG. 19 and description of the numerals to be assigned to constituent elements is appropriately omitted. However, configurations of constituent elements other than the inspection sections (for example, the first support section 21, respective parts which configure the conveyance direction adjustment element and so forth) are substantially the same as the configurations of the above-described embodiment and the modified example and therefore repetitive description of these parts is avoided by quoting the preceding description in principle. Incidentally, in FIG. 19, the inspection object conveyance surface is the front surface of the conveyor belt 6 onto which the inspection object is sucked and bonded, and the inspection object conveyance direction is indicated by an arrow Y which is parallel with the conveyance surface. In addition, a width direction of the inspection object which is orthogonal to the inspection object conveyance direction Y is indicated by an arrow X.

As illustrated in FIG. 19, in the first suction conveyance unit 1 of the image inspection device 200 g, the CIS 11 b as the first inspection section is installed relatively on the upstream side (the left side in FIG. 19) of the inspection object conveyance direction Y. The CIS 11 b is an element which inspects the image on the front surface of the inspection object in the linear inspection region on the inspection object which is parallel with the width direction X, an inspection range of the CIS 11 b sufficiently covers a widthwise length of the image on the inspection object to be inspected, and it is possible to obtain data on all images which are formed on the inspection object from pixel data which is read out of each of many linear inspection regions which are arrayed in the conveyance direction Y. The depth of field, the arrangement accuracy and so forth of the CIS 11 b are as described above.

As illustrated in FIG. 19, in the first suction conveyance unit 1 of the image inspection device 200 g, the camera 11 a as the third inspection section is installed on the downstream side (the right side in FIG. 19) of the CIS 11 b of the inspection object conveyance direction Y. The camera 11 a is an element which inspects the image on the front surface of the inspection object in the planar inspection region which is parallel with the inspection object conveyance surface and has a rectangular inspection range which allows reading of an image of a predetermined area (for example, a rectangular range of about 50 mm×100 mm) which has a visually effective dimension in both the conveyance direction Y and the width direction X just like, for example, a QR code. The depth of field, the arrangement accuracy and so forth of the camera 11 a are as described above.

As illustrated in FIG. 19, the camera 11 a is loaded on a sliding-type moving mechanism and is made movable in the inspection object width direction X, that is, the direction which is parallel with the linear inspection region on the front surface of the inspection object. In the following, the moving mechanism will be described. A guide rail 50 is fixed to a frame of the image inspection device 200 g in parallel with the width direction X above the first suction conveyance unit 1. A moving body 51 is installed on the guide rail 50 to be movable along the width direction X. The moving body 51 is manually set to an optional position. However, the moving body 51 may be moved by a driving source (not illustrated). In this case, the moving body 51 may be set to the optional position automatically by the driving source in accordance with a position of the image along the width direction X in the planar inspection region to be detected on the basis of detection information from the upstream-side CIS 11 b or various control information and so forth from the control unit. Further, a semi-automatic system that the driving source operates only when an operator closes a conduction switch and thereby the moving body 51 moves may also be adopted. An upper end of a stationary plate 52 is attached to a side face of the moving body 51, and the stationary plate 52 is hanged more downward than the guide rail 50. The aforementioned camera 11 a is attached to an almost central part of a front surface of the stationary plate 52. The camera 11 a includes a lens part 53 the focus of which is adjusted by turning a focus ring and a rotation mechanism part 54 which rotates the lens part 53 in a rotation direction which is indicted by an arrow Z. An angle that the lens part 53 is allowed to rotate by the rotation mechanism part 54 is about 90 degrees. Both the focus ring of the lens part 53 and the rotation mechanism part 54 are manually operated and when operating the focus ring and the rotation mechanism part 54, the operator works by opening an open/close door which is located on the front surface of the frame of the image inspection device 200 g and inserting his/her hand into a place concerned. One end of a bendable cable carrier 55 is coupled to the stationary plate 52 to which the camera 11 a is attached. The cable carrier 55 bends and changes its direction by about 180 degrees, and the other-end side of the cable carrier 55 is arranged along the guide rail 50 toward one end of the guide rail 50. A control line 56 of the camera 11 a is drawn around along the cable carrier 55 and is connected to the control unit (not illustrated).

Although not illustrated, the second suction conveyance unit 2 is arranged adjacent to the first suction conveyance unit 1 so as to be turned upside down relative to the first suction conveyance unit 1. Also in the second suction conveyance unit 2, the CIS 12 b as the second inspection section is arranged relatively on the upstream side and the camera 12 a as the fourth inspection section is arranged relatively on the downstream side in arrangement which is similar to the arrangement of the CIS 11 b and the camera 11 a of the first suction conveyance unit 1. Incidentally, in the second suction conveyance unit 2, the CIS 12 b and the camera 12 a which is loaded on the moving mechanism are arranged under the second suction conveyance unit 2 facing upward contrary to the CIS 11 a and the camera 12 a of the first suction conveyance unit 1 and inspect the images on the back surface of the inspection object.

According to the image inspection device 200 g of the seventh modified example, it becomes possible to perform linear inspection region-based inspection on the images which are printed on the inspection object by the upstream-side CIS 11 b and to perform inspection of the images (for example, a bar code image and so forth) in a two-dimensional planar inspection region which is formed on a specific position of the inspection object by the downstream side camera 11 a. In this case, it is preferable to properly set a position of the camera 11 a along the width direction X in advance by such manual, automatic or semi-automatic operation as described above in accordance with the position of the planar inspection area which is formed on the inspection object along the width direction X. In addition, it is also preferable to set the rectangular inspection range of the camera 11 a to an appropriate arrangement in a vertically long arrangement and a horizontally long arrangement in advance in accordance with the shape of the image in the planar inspection region on the inspection object by operating the rotation mechanism part 54 of the camera 11 a. Incidentally, a height of the camera 11 a which is measured from the conveyance surface is fixed, and the sheet-shaped inspection object (the sheet paper) is sucked and fixed onto the conveyance surface of the conveyor belt 6 across the entire surface and is in the stable state. Therefore, although the possibility that the once focused camera 11 a may become out of focus is low, focusing of the camera 11 a may be confirmed as needed.

In addition, according to the image inspection device 200 g, the inspection object that the suction conveyance unit concerned conveys as a conveyance object is the sheet-shaped paper. Accordingly, unlike a case of conveying a bag and so forth having a structure that two sheets of paper are superimposed in order to form a space in the bag, in the image inspection device 200 g, the sheet-shaped inspection object is sucked onto the conveyance surface of the conveyor belt 6 across the entire surface and is conveyed in a state where the vertical position is fixed. Accordingly, it becomes possible to sufficiently exhibit the high reading accuracy of the CIS 11 b which is shallower in depth of field than the camera 11 a and for which the high arrangement accuracy is required in order to obtain the expected reading accuracy.

In addition, inspection of the inspection object on the first suction conveyance unit 1 of the image inspection device 200 g is performed in the following order: first, linear inspection region-based inspection is performed by the CIS 11 b on the upstream side; and then inspection of the planar inspection region is performed by the downstream-side camera 11 a. Therefore, in a case where behavioral abnormality of the inspection object and image abnormality are detected in line-by-line image inspection on the upstream side, a step of inspecting the planar inspection region on the downstream side is suspended by using this abnormality detection as a trigger and thereby it becomes possible to omit useless inspection of the inspection object. A sorting device or a distribution device may be installed on the downstream side of the image inspection device 200 g for an inspection object in which abnormality is detected so as to sort or distribute the inspection object in which the abnormality is detected, then to guide the sorted or distributed inspection object to a path which is different from a path for an inspection object having no trouble and then to collect the sorted or distributed inspection object. Incidentally, in a case where the abnormality is detected in inspection by the CIS 11 b, inspection by the camera 11 a may be continued as it is and in regard to the inspection object in which the abnormality is detected, detection of abnormality may be left on inspection record, and image inspection may be performed again by inputting the inspection object in which the abnormality is detected on an inspection line later.

Further, according to the image inspection device 200 g, even when a jam occurs on the inspection object delivery section which is located between the first suction conveyance unit 1 and the second suction conveyance unit 2, at least the inspection section which is located on the downstream side of the first suction conveyance unit 1 is the camera 11 a which is movable in the width direction X and therefore in a case where the jam occurs in the vicinity of the camera 11 a, it is possible to secure a workspace by moving the camera 11 a in the width direction X and thereby to manually perform jam clearing work more easily. Incidentally, in a case where the configuration of the first suction conveyance unit 1 is as described above and in the second suction conveyance unit 2, the upstream side inspection section is configured by the camera 12 a which is movable in the width direction X and the downstream side inspection section is configured by the CIS 12 b, then the jam clearing work to be performed when the jam occurs on the delivery section as described above becomes even more easily.

Further, in the image inspection device 200 g, when positional displacement of the inspection object occurs in the width direction X while the inspection object is conveyed, occurrence of a trouble that the planer inspection region does not enter the inspection range of the camera 11 a which is set in alignment with the position of the planar inspection region (for example, the QR code) to make it impossible to perform inspection is conceivable. However, according to the image inspection device 200 g, the CIS 11 b of the first suction conveyance unit 1 is able to detect positions of edges of the inspection object in the width direction X at both ends of the linear inspection region. Accordingly, in a case where the CIS 11 b performs inspection of the linear inspection region a plurality of times and obtains a plurality of pieces of data on the positions of the edges which are located on the same sides in the width direction X, the control unit into which the plurality of pieces of data are input is able to decide whether the inspection object is displaced in the width direction X at once by comparing the plurality of pieces of data with one another and is able to calculate an amount of displacement immediately in a case where the inspection object is displaced in the width direction X. Then, the control unit controls the moving mechanism for the camera 11 a which is located on the downstream side in accordance with the displacement amount and thereby it becomes possible to correct the position of the camera 11 a, in the width direction X, to make a new position of the planar inspection region and the inspection range of the camera 11 a match each other and thereby to make the camera 11 a properly perform inspection of the planar inspection region.

FIG. 20 is a schematic front view illustrating an eighth modified example.

In an image inspection device 200 h according to the eighth modified example, the configuration of the conveyance mechanism centering around the first suction conveyance unit 1 and the second suction conveyance unit 2 is the same as the configuration of the conveyance mechanism of the image inspection device 200 according to the embodiment. Thus, the numerals which are the same as those in FIG. 2 are assigned to the corresponding constitutional elements and description thereof is omitted by quoting the description of the embodiment. In addition, the kind and the number of the inspection sections and a way of arraying the inspection sections along the inspection object conveyance direction according to the kind is the same as those of the third modified example of the embodiment which is illustrated in FIG. 15.

That is, as illustrated in FIG. 20, in the image inspection device 200 h, the camera 11 a as the first inspection section and the CIS 11 b as the third inspection section are arrayed in this order when seen from the upstream side on the first suction conveyance unit 1, and the camera 12 a as the second inspection section and the CIS 12 b as the fourth inspection section are arrayed in this order when seen from the upstream side on the second suction conveyance unit 2. The configurations of the CISs 11 b and 12 b and the cameras 11 a and 12 a are as described before description of this modified example. However, as a more specific arrangement example of the inspection sections, the height of the CISs 11 b and 12 b which is measured from the conveyance surface of the conveyor belt 6 is set to about 24 mm, the height of the cameras 11 a and 12 a which is measured from the conveyance surface of the conveyor belt 6 is set to about 120 mm in view of the fact that the cameras 11 a and 12 a are area cameras each having a wide-angle inspection range. In addition, the cameras 11 a and 12 a are loaded on the sliding-type moving mechanism similarly to the cameras in the seventh modified example which is illustrated in FIG. 19. As the description of the moving mechanism, the description of the moving mechanism of the seventh modified example will be quoted.

In the first and second suction conveyance units 1 and 2, the force of sucking the inspection object which is conveyed is higher in a state where the inspection object is sucked onto the part extending to the downstream side of the conveyor belt 6 and is conveyed with most of the holes closed than in a state where the inspection object is sucked only onto the upstream-side part of the conveyor belt 6 and is conveyed with most of the hole not closed. That is, the force of sucking the inspection object is relatively weak on the upstream side of the conveyer belt 6 and displacement of a height-direction position of the inspection object is easy to occur. In contrast, the suction force is relatively strong on the downstream side of the conveyor belt 6 and displacement of the height-direction position of the inspection object is difficult to occur. Accordingly, in the image inspection device 200 h, the CISs 11 b and 12 b which are relatively high in required arrangement accuracy (shallow in depth of field) are arranged relatively on the downstream side of the inspection object conveyance direction, and the cameras 11 a and 12 a which are relatively low in required arrangement accuracy (deep in depth of field) are arranged relatively on the upstream side of the inspection object conveyance direction. Therefore, it becomes possible to arrange the different kinds of the inspection sections with arrangement accuracies which are necessary to make the inspection sections function with their expected inspection accuracies and it becomes possible to surely secure the levels of the expected inspection accuracies of the respective inspection sections.

As described above, in the seventh modified example which is described with reference to FIG. 19 and the eighth modified example which is described with reference to FIG. 20, the cameras 11 a and 12 a are arranged on the upstream sides of the respective suction conveyance units 1 and 2 respectively, the CISs 11 b and 12 b are arranged on the downstream sides of the respective suction conveyance units 1 and 12 respectively, and the cameras 11 a and 12 a are made to be movable in a direction which is parallel with the linear inspection region. However, in a case where the images which are formed on the inspection object as objects for inspection are fixedly present only on specific positions in a direction which is parallel with the linear inspection region and conveyance operations of the suction conveyance units 1 and 2 are stable, and therefore the position of the inspection object in the direction which is parallel with the linear inspection region is stable, positions of the cameras 11 a and 12 a may be fixed in alignment with the positions of the image in the direction which is parallel with the linear inspection region without making the cameras 11 a and 12 a movable.

A ninth modified example will be described with reference to FIG. 1.

In the modified examples which have been described so far, in a case where only the CIS is arranged on the suction conveyance unit concerned and in a case where both the IIS and the camera are arranged on the suction conveyance unit concerned, in the both cases, there are cases where both the CIS and the camera are arranged relatively on the upstream side of the suction conveyance unit concerned and there are also cases where both the CIS and the camera are arranged relatively on the downstream side of the suction conveyance unit concerned. In a modified example which will be described in the following, on which side the CIS and the camera are to be arranged is determined between the upstream side and the downstream side of the conveyance direction on the basis of a viewpoint of nipping force as to which inspection object nipping force (or conveying force) is larger between the nipping force of the device on the upstream side and the nipping force of the device on the downstream side between two mutually adjacent devices in the printing device 100, the image inspection device 200, and the post-processing device 300 which are illustrated in FIG. 1 as well as a view point of the inspection object conveyance path as to which inspection object conveyance path 102 of which device is more complicated between the conveyance path of the device on the upstream side and the conveyance path of the device on the downstream side also between the two mutually adjacent devices in the printing device 100, the image inspection device 200, and the post-processing device 300.

In FIG. 1, in a case where the nipping force of the printing device 100 is larger than the nipping force of the image inspection device 2 which is located on the downstream side of the printing device 100, there are cases where conveyance of the inspection object becomes unstable on the upstream side of the image inspection device 200 which is adjacent to the printing device 100, and the height-direction position of the inspection object fluctuates irregularly, and therefore it is preferable to arrange the camera (11 a or 12 a) which is the inspection section for which no high arrangement accuracy is required on the uppermost stream side of the image inspection device 200.

In FIG. 1, in a case where the nipping force of the image inspection device 200 exceeds the nipping force of the printing device 100, conveyance of the inspection object is stable on the upstream side of the image inspection device 200 and the height-direction position of the inspection object is difficult to fluctuate, and therefore it is preferable to arrange the CIS (11 b or 12 b) which is the inspection section for which the high arrangement accuracy is required on the uppermost stream side of the image inspection device 200.

In FIG. 1, in a case where the conveyance path 102 of the printing device 100 which is connected to the upstream side of the image inspection device 200 is not linear and is bent just like a conveyance path 102 a which is indicated by a dashed line, the possibility that a paper jam may occur on the uppermost-stream side of the conveyance path in the image inspection device 200 is increased. Accordingly, the camera (11 a or 12 a) is used as the inspection section to be arranged on the uppermost-stream side of the image inspection device 200 and the camera concerned is made movable in the width direction X by the aforementioned sliding type moving mechanism. Thereby, in a case where the paper jam occurs on the uppermost-stream side of the conveyance path in the image inspection device 200, it becomes possible to secure a workspace for jam clearance by moving the camera concerned and thereby the work for jam clearance is facilitated.

In FIG. 1, in a case where the conveyance path 102 of the post-processing device 300 which is connected to the downstream side of the image inspection device 200 is not linear and is bent just like the conveyance path 102 a which is indicated by the dashed line, the possibility that a paper jam may occur on the lowermost-stream side of the conveyance path of the image inspection device 200 is increased. Accordingly, the camera (11 a or 12 a) is used as the inspection section to be arranged on the lowermost-stream side of the image inspection device 200, and the camera concerned is made movable in the width direction X by the aforementioned sliding type moving mechanism. Thereby, in a case where the paper jam occurs on the lowermost-stream side of the conveyance path in the image inspection device 200, it becomes possible to secure a workspace for jam clearance by moving the camera concerned and thereby the work for jam clearance is facilitated.

Incidentally, in the present embodiment and the modified examples thereof, the first suction conveyance unit 1 is arranged in such a manner that the conveyance surface is located on the upper surface side and the second suction conveyance unit 2 is arranged in such a manner that the conveyance surface is located on the lower surface side and is arranged adjacent to the conveyance surface of the first suction conveyance unit 1 along the inspection object conveyance direction. However, there is no particular limitation on the paper conveyance direction relative to the first and second suction conveyance units 1 and 2. That is, for example, although in FIG. 2, the inspection object is illustrated to be conveyed from left to right, the inspection object may be conveyed from right to left. In addition, in FIG. 2, arrangement of the first suction conveyance unit 1 and the second suction conveyance unit 2 may be changed in such a manner that the first suction conveyance unit 1 is located on the right side and the second suction conveyance unit 2 is located on the left side. Also, in this case, the paper may be conveyed either rightward or leftward.

Incidentally, although belt suction conveyance using a fan is described as the inspection object conveyance element in the present embodiment and the modified examples thereof, electrostatic suction conveyance, bonding conveyance by bonding using roller conveyance, and other types of bonding conveyance using certain bonding elements may be used. As bonding conveyance using the roller conveyance which is one example of the bonding conveyance, for example, it is possible to convey paper by making the paper bond to a roller by a roller conveyance element in which a bonding agent having a bond strength of such an extent that the inspection object does not fall under its own weight is applied onto a roller surface, and it is also possible to use this roller conveyance member in place of the suction conveyance unit of the present embodiment. Further, as bonding conveyance using other bonding elements, it is also possible to use bonding conveyance using belt conveyance in which the inspection object is conveyed by applying the above-described bonding agent onto the conveyor belt. Incidentally, in a case of performing these types of bonding conveyance, a pee-ling section which peels the paper from the bonding agent on the conveyor belt or the roller may be installed. Inspection object conveyance is not limited to the belt suction conveyance using the fan just like the conveyance of the present embodiment in this way. In addition, even in a case of performing the electrostatic suction conveyance and the bonding conveyance by the first and second suction conveyance units 1 and 2, the inspection section(s) may be arranged on the downstream sides of the first and second suction conveyance units 1 and 2. This is because, for example, also in a case of performing the electrostatic suction conveyance, an electrostatic suction area becomes larger on the downstream aide than on the upstream side and suction is stabilized. In addition, also in a case of performing bonding conveyance by using the plurality of rollers in the first and second suction conveyance units 1 and 2, suction is stabilized and conveyance is secured more in a state where the inspection object is conveyed by being bonded using two or more roller on the downstream side than in a state where the inspection object is conveyed by being bonded using one roller on the upstream side.

Further, as the one first inspection section (or the one second inspection section) which is installed on the first conveyance unit (or the second conveyance unit), CIS (contact image sensor), a camera, a barcode-reader and so forth may be specifically given by way of example; however, the first inspection section (or the second inspection section) may be an inspection device having function of reading images on other principles. Further, the first inspection section (or the second inspection section) may include other device having function except inspection as well as the inspection device.

Incidentally, although there are cases where the drawings which are appended to the present specification are schematically expressed in a state where scales, an aspect dimension ratio, shapes and so forth are appropriately changed from real ones for the convenience in view of illustration and comprehensiveness, these are merely examples and do not limit interpretation of the present invention. Accordingly, the present invention is not limited by the embodiment and the modified examples thereof which are described using the appended drawings, and all the other feasible aspects, embodiments, operation technologies and so forth which would be conceived of by a person skilled in the art on the basis of the present embodiment and the modified examples thereof are included in the scope of the present invention.

Sheet Feeders of Respective Aspects in Present Embodiment and Modified Examples Thereof and Effects Thereof

The image inspection devices 200, 200 a to 200 f according to a first aspect each include:

the first suction conveyance unit 1 which is arranged in such a manner that the conveyance surface on which the sheet-shaped inspection object is sucked and conveyed is located on the upper surface side;

the second suction conveyance unit 2 which is arranged adjacent to the conveyance surface of the first suction conveyance unit 1 along the inspection object conveyance direction in such a manner that the conveyance surface on which the sheet-shaped inspection object is sucked and conveyed is located on the lower surface side;

the first inspection section 11 which inspects the images on the front surface of the inspection object which is conveyed by the first suction conveyance unit 1; and

the second inspection section 12 which inspects the images on the back surface of the inspection object which is conveyed by the second suction conveyance unit 2.

According to the image inspection devices 200, 200 a to 200 f according to the first aspect, the inspection object is stably conveyed in a state of being sucked and held on the upper surface side of the first suction conveyance unit 1, is stably conveyed in a state of being sucked and held on the lower surface side of the second suction conveyance unit 2, and is stably delivered between the first suction conveyance unit 1 and the second suction conveyance unit 2. Therefore, since the position and the posture of the inspection object are stabilized while the inspection object is conveyed, the expected accuracy is maintained in inspection by the first inspection section 11 and the second inspection section 12.

In the image inspection device 200 a according to a second aspect,

the first suction conveyance unit 1 and the second suction conveyance unit 2 are arranged on the upstream side and the downstream side respectively along the inspection object conveyance direction, and

the conveyance surface of the second suction conveyance unit 2 has the angle which is inclined downward toward the downstream side relative to the conveyance surface of the first suction conveyance unit 1 and which is necessary for stable conveyance of the inspection object, in the image inspection devices according to the first aspect.

According to the image inspection device 200 a according to the second aspect, since the conveyance surface of the second suction conveyance unit 2 which is located on the downstream side of the inspection object conveyance direction is inclined downward toward the downstream side relative to the conveyance surface of the first suction conveyance unit 1 which is located on the upstream side by the angle which is necessary for stable conveyance of the inspection object, the top edge of the inspection object which is conveyed from the first suction conveyance unit 1 to the second suction conveyance unit 2 is pressed against the conveyance surface of the second suction conveyance unit 2 and therefore is surely sucked and held on the conveyance surface and is stably conveyed to the downstream side by the second suction conveyance unit 2 even when the top edge hangs downward from the conveyance surface of the first suction conveyance unit 1 because of paper quality and so forth.

In the image inspection device 200 a according to a third aspect, the angle which is inclined downward toward the downstream side of the conveyance surface of the second suction conveyance unit 2 is set in accordance with image forming conditions when forming the images on the inspection object, in the image inspection device 200 a according to the second aspect.

According to the image inspection device 200 a according to the third aspect, the angle which is inclined downward toward the downstream side of the conveyance surface of the second suction conveyance unit 2 is appropriately set in accordance with the image forming conditions when forming the images on the inspection object such as, for example, the kind of the inspection object, the orientation of the inspection object, the printing amount, and the arrangement balance of the printing range in the image forming surface of the inspection object. Accordingly, the effect that the top edge of the inspection object which is conveyed from the first suction conveyance unit 1 to the second suction conveyance unit 2 is pressed against the conveyance surface of the second suction conveyance unit 2 and thereby is surely sucked and held on the conveyance surface and is stably conveyed to the downstream side by the second suction conveyance unit 2 becomes more certain.

The image inspection devices 200, 200 a to 200 f according to a fourth aspect each have:

the first support section 21 to which the first inspection section 11 is attached and which is supported on the frame of the image inspection device at the three places to be movable and is positioned relative to the first suction conveyance unit 1; and

the second support section 22 to which the second inspection section 12 is attached and which is supported on the frame of the image inspection device at the three places to be movable and is positioned relative to the second suction conveyance unit 2, in the image inspection devices according to the first aspect.

According to the image inspection devices 200, 200 a to 200 f according to the fourth aspect, the first support section 21 and the send support section 22 are supported on the frame of the image inspection device concerned at the three places to be rotatable respectively. Therefore, even in a case where the external force is applied to the frame and the frame is distorted due to inclined arrangement of the image inspection device and so forth, since no harmful force is transmitted from the frame to the first support section 21 and the second support section 22, the first support section 21 and the second support section 22 are not distorted. Accordingly, the positional relations between the first inspection section 11 which is installed on the first support section 21 and the first suction conveyance unit 1 and between the second inspection section 12 which is installed on the second support section 22 and the second suction conveyance unit 2 do not change from the normal states respectively, and the positional relation between the first suction conveyance unit 1 and the second suction conveyance unit 2 does not change. Accordingly, since the respective conveyance surfaces of the first suction conveyance unit 1 and the second suction conveyance unit 2 maintain a mutually matched state and the inspection object is properly inspected by the two inspection sections while being continuously conveyed, the inspection accuracy is not lowered.

In the image inspection device 200 b according to a fifth aspect, part of the conveyance surface of the first suction conveyance unit 1 and part of the conveyance surface of the second suction conveyance unit 2 are mutually superimposed, in the image inspection devices according to the first aspect.

According to the image inspection device 200 b according to the fifth aspect, since part of the conveyance surface of the first suction conveyance unit 1 and part of the conveyance surface of the second suction conveyance unit 2 are mutually superimposed, the inspection object is directly delivered between the first suction conveyance unit 1 and the second conveyance unit 2 and conveyance of the inspection object is smoothly performed. In addition, it is not necessary to install the element for delivering the inspection object between the first and second suction conveyance units 1 and 2, and the configuration is simplified in comparison with a case where this member is installed.

The image inspection device 200 c according to a sixth aspect further includes:

the third inspection section 11 b which is arranged at the position which is different from the position of the first inspection section 11 a in the inspection object conveyance direction and inspects the images on the front surface of the inspection object; and

the fourth inspection section 12 b which is arranged at the position which is different from the position of the second inspection section 12 a in the inspection object conveyance direction and inspects the images on the back surface of the inspection object.

On the first suction conveyance unit 1, of the first inspection section 11 a and the third inspection section 11 b, the inspection section 11 b for which the relatively high arrangement accuracy is required is arranged relatively on the downstream side of the inspection conveyance direction, and the inspection section 11 a is arranged relatively on the upstream side of the inspection object conveyance direction.

On the second suction conveyance unit 2, of the second inspection section 12 a and the fourth inspection section 12 b, the inspection section 12 b for which the relatively high arrangement accuracy is required is arranged relatively on the downstream side of the inspection conveyance direction, and the inspection section 12 a is arranged relatively on the upstream side of the inspection object conveyance direction.

According to the image inspection device 200 c according to the sixth aspect, although two inspection sections are installed respectively on the first suction conveyance unit 1 and the second suction conveyance unit 2, also on either suction conveyance unit, of the two inspection sections, the inspection section for which the required arrangement accuracy is relatively high is arranged relatively on the downstream side of the inspection object conveyance direction, and the inspection section for which the required arrangement accuracy is relatively low is arranged relatively on the upstream side of the inspection object conveyance direction. In the first and second suction conveyance units 1 and 2, since the stability of the inspection object which is conveyed by suction is higher in the state where the inspection object is conveyed while being sucked onto the part which reaches the downstream side of the suction conveyance unit concerned than in the case where the inspection object is conveyed while being sucked onto only the upstream side part of the suction conveyance unit concerned, arrangement of the respective inspection sections on the respective suction conveyance units 1 and 2 is made as mentioned above and thereby it becomes possible to arrange the respective inspection sections with the arrangement accuracies which are necessary to make the respective inspection sections function with the expected inspection accuracies and to maintain inspection object inspection accuracies at expected levels of the respective inspection sections.

The image inspection device 200 g according to the seventh aspect further includes:

the third inspection section which is arranged at the position which is different from the position of the first inspection section 11 a along the inspection object conveyance direction and inspects the images on the front surface of the inspection object; and

the fourth inspection section 12 b which is arranged at the position which is different from the position of the second inspection section 12 a along the inspection object conveyance direction and inspects the images on the back surface of the inspection object.

One of the first inspection section 11 a and the third inspection section 11 b is arranged relatively on the upstream side of the inspection object conveyance direction and inspects the images on the front surface of the inspection object in the linear inspection region which is vertical to the inspection object conveyance direction and is parallel with the conveyance surface, and the other of the first inspection section 11 a and the third inspection section 11 b is arranged relatively on the downstream side of the inspection object conveyance direction and inspects the images on the front surface of the inspection object in the planar inspection region which is parallel with the conveyance surface, and

one of the second inspection section 12 a and the fourth inspection section 12 b is arranged relatively on the upstream side of the inspection object conveyance direction and inspects the images on the back surface of the inspection object in the linear inspection region which is vertical to the inspection object conveyance direction and is parallel with the conveyance surface, and the other of the second inspection section 12 a and the fourth inspection section 12 b is arranged relatively on the downstream side of the inspection object conveyance direction and inspects the images on the back surface of the inspection object in the planar inspection region which is parallel with the conveyance surface.

According to the image inspection device 200 g according to the seventh aspect, in the respective suction conveyance units 1 and 2, in a case where behavior abnormality and image abnormality of the inspection object are detected in inspection of the images in the linear inspection region by the upstream-side inspection section, the step of inspecting the images in the planar inspection region by the downstream side inspection section is suspended by using this abnormality detection as the trigger and thereby it becomes possible to eliminate useless inspection of the images on the inspection object concerned.

In the image inspection device 200 g according to an eight aspect,

the other of the first inspection section 11 a and the third inspection section 11 b is movable in the direction which is parallel with the linear inspection region, and

the other of the second inspection section 12 a and the fourth inspection section 12 b is movable in the direction which is parallel with the linear inspection region, in the image inspection device according to the seventh aspect.

According to the image inspection device 200 g according to the eighth aspect, even when the inspection object jam occurs between the first suction conveyance unit 1 and the second suction conveyance unit 2, since the inspection section which is located on the downstream side of the first suction conveyance unit 1 is the inspection section which is movable in the direction which is the inspection object width direction and is parallel with the linear inspection region, in a case where the jam occurs in the vicinity of the inspection section concerned, it is possible to perform manual jam clearance work more easily by moving the inspection section concerned in the direction which is parallel with the linear inspection region.

In the image inspection devices 200, 200 a to 200 f accruing to a ninth aspect, on at least one of the first suction conveyance unit 1 and the second suction conveyance unit 2, at least one of the first inspection section 11 a and the second inspection section 12 a is installed on at least one of the upstream-side end and the downstream-side end of the inspection object conveyance direction.

According to the image inspection devices 200, 200 a to 200 f according to the ninth aspect, since the first and second suction conveyance units 1 and 2 are mechanisms which convey the sheet-shaped inspection object in a state where the inspection object is sucked onto the conveyance surfaces thereof, the conveyance surfaces are made open, and there exist no constitutional elements of the first suction conveyance unit 1 and the second suction conveyance unit 2 which would become obstacles. Then, in the open conveyance surfaces, parts on which the first inspection section 11 a and the second inspection section 12 a are arranged are limited to only at least one of the upstream-side end and the downstream-side end. Accordingly, the possibility that the sheet-shaped inspection object may be jammed on the conveyance surface(s) of the first suction conveyance unit 1 and/or the second suction conveyance unit 2 is low. However, even when the inspection object jam occurs, most parts of the conveyance surfaces are made open, the first inspection section 11 a and the second inspection section 12 a which are arranged on the ends of the conveyance surfaces do not become the obstacles when removing the jammed inspection object from the conveyance surface concerned, and it is possible to perform the jam clearance work with ease.

In the image inspection devices 200 c and 200 f according to a tenth aspect, at least one of the first inspection section 11 a and the second inspection section 12 a is installed on the downstream-side end of at least one of the first suction conveyance unit 1 and the second suction conveyance unit 2, in the image inspection devices according to the first aspect.

According to the image inspection devise 200 c and 200 f according to the tenth aspect, on the first suction conveyance unit 1 and the second suction conveyance unit 2, the stability which is attained by suction of the inspection object which is conveyed is higher in the state where the inspection object is sucked onto the conveyance surface across the wider area reaching the downstream side of the conveyance surface and the effect of suction acts on most of the conveyance surface than in the state where the inspection object is sucked only onto the upstream side of the conveyance surface and the effect of suction does not act on most of the conveyance surface. Accordingly, owing to installation of the first inspection section 11 b and the second inspection section 12 b respectively on the downstream-side ends of the first suction conveyance unit 1 and the second suction conveyance unit 2 in the conveyance direction, it becomes possible to inspect the images on the inspection object in a state where holding of the inspection object is certain and the position and the posture of the inspection object are stabilized and to obtain the effect that the inspection accuracy is improved.

In the image inspection devices 200, 200 a to 200 e according to an eleventh aspect, at least one of the first inspection section 11 a and the second inspection section 12 a is installed on the upstream-side end of at least one of the first suction conveyance unit 1 and the second suction conveyance unit 2, in the image inspection devices according to the first aspect.

According to the image inspection devices 200, 200 a to 200 e according to the eleventh aspect, since the first inspection section 11 or 11 a and the second inspection section 12 or 12 a are arranged in the vicinity of the upstream-side ends of the first suction conveyance unit 1 and the second suction conveyance unit 2 respectively, in a case where the results of image detection by the first inspection section 11 or 11 a and the second inspection section 12 or 12 a are utilized on the downstream side, it is preferable to arrange the inspection sections in the vicinity of the upstream side ends of the suction conveyance units because sufficient time is secured for utilization of the image detection results. For example, in a case where post-processing is performed on the inspection object on the basis of the inspection results in the post-processing device which is located on the rear stage of the image inspection devises 200, 200 a to 200 e, since the first inspection section 11 or 11 a and the second inspection section 12 or 12 a are located on the upstream sides of the first suction conveyance unit 1 and the second suction conveyance unit 2 respectively, the post-processing device is able to obtain the inspection results sooner than a case where the inspection sections are located on the downstream sides of the first and second suction conveyance units 1 and 2 respectively and to execute necessary post-processing without delay.

Incidentally, the image inspection devices according to the ninth aspect to the eleventh aspect include not only the illustrated case where two sets of one suction conveyance unit and one inspection section are arrayed in mutually turned upside down postures along the inspection object conveyance direction but also a case where only one set of the suction conveyance unit and the inspection section is installed. That is, in the illustrated image forming apparatus, also the image inspection device from which the second suction conveyance unit 2 and the second inspection section 12 are deleted so as to be configured only of the remaining first suction conveyance unit 1 and the remaining first inspection section 11 is included in the image inspection devices according to the ninth to eleventh aspects, and also the image inspection device from which the first suction conveyance unit 1 and the first inspection unit 11 are deleted so as to be configured only of the remaining second suction conveyance unit 2 and the remaining second inspection section 12 is included in the image inspection devices according to the ninth to eleventh aspects. In this case, installation of the intermediate guide plate 15 is unnecessary. In this case, the same effects as the above-described effects in the illustrated case are obtained.

DESCRIPTION OF REFERENCE SIGNS

-   1 . . . first suction conveyance unit as a first conveyance unit -   2 . . . second suction conveyance unit as a second conveyance unit -   11 . . . first inspection section -   12 . . . second inspection section -   11 a, 12 a . . . one inspection section (camera) for which a     relatively low arrangement accuracy is required in the inspection     sections of the suction conveyance unit -   11 b, 12 b . . . the other inspection section (CIS) for which a     relatively high arrangement accuracy is required in the inspection     sections of the suction conveyance unit -   21 . . . first support section -   22 . . . second support section -   35 . . . fixing pin which configures a conveyance direction     adjustment element of the suction conveyance unit -   36 . . . positioning hole which configures the conveyance direction     adjustment element of the suction conveyance unit -   37 . . . movable pin which configures the conveyance direction     adjustment element of the suction conveyance unit -   38 . . . operation member which configures the conveyance direction     adjustment element of the suction conveyance unit -   39 . . . slot which configures the conveyance direction adjustment     element of the suction conveyance unit -   40 . . . operation handle which configures the conveyance direction     adjustment element of the suction conveyance unit -   42 . . . hanging prevention member -   43 . . . skew correction roller -   50 . . . guide rail which configures a camera moving mechanism -   51 . . . moving body which configures the camera moving mechanism -   52 . . . stationary plate which configures the camera moving     mechanism -   54 . . . rotating mechanism section which configures the camera     moving mechanism -   55 . . . cable carrier which configures the camera moving mechanism -   200, 200 a to 200 g . . . image inspection device -   A, B, C . . . fulcrum which rotatably supports the support section     on a frame of the image inspection device -   X . . . inspection object width direction -   Y . . . inspection object conveyance direction -   Z . . . lens portion rotation direction by the rotating mechanism     section 

1. An image inspection device comprising: a first conveyance unit which is arranged in such a manner that a conveyance surface on which a sheet-shaped inspection object is conveyed is located on an upper surface side; a second conveyance unit which is arranged adjacent to the conveyance surface of the first conveyance unit along an inspection object conveyance direction in such a manner that a conveyance surface on which the sheet-shaped inspection object is conveyed is located on a lower surface side; a first inspection section which inspects an image on a front surface of the inspection object which is conveyed by the first conveyance unit; and a second inspection section which inspects an image on a back surface of the inspection object which is conveyed by the second conveyance unit.
 2. The image inspection device according to claim 1, wherein the first conveyance unit and the second conveyance unit are arranged on an upstream side and a downstream side respectively along the inspection object conveyance direction, and the conveyance surface of the second conveyance unit has an angle which is inclined downward toward the downstream side relative to the conveyance surface of the first conveyance unit for stable conveyance of the inspection object.
 3. The image inspection device according to claim 2, wherein the angle of the conveyance surface of the second conveyance unit which is inclined downward toward the downstream side is set in accordance with image forming conditions in a case of forming images on the inspection object.
 4. The image inspection device according to claim 1, further comprising: a first support section to which the first inspection section is attached and which is rotatably supported on a frame of the image inspection device at three points and is positioned relative to the first conveyance unit; and a second support section to which the second inspection section is attached and which is rotatably supported on the frame of the image inspection device at three points and is positioned relative to the second conveyance unit.
 5. The image inspection device according to claim 1, wherein part of the conveyance surface of the first conveyance unit and part of the conveyance surface of the second conveyance unit are mutually superimposed.
 6. The image inspection device according to claim 1, further comprising: a third inspection section which is arranged at a position which is different from the position of the first inspection section along the inspection object conveyance direction and inspects the image on the front surface of the inspection object; and a fourth inspection section which is arranged at a position which is different from the position of the second inspection section along the inspection object conveyance direction and inspects the image on the back surface of the inspection object, wherein on the first conveyance unit, in the first inspection section and the third inspection section, one inspection section which is relatively high in arrangement accuracy is arranged relatively on the downstream side of the inspection object conveyance direction and the other inspection section is arranged relatively on the upstream side of the inspection object conveyance direction, and on the second conveyance unit, in the second inspection section and the fourth inspection section, one inspection section which is relatively high in arrangement accuracy is arranged relatively on the downstream side of the inspection object conveyance direction and the other inspection section is arranged relatively on the upstream side of the inspection object conveyance direction.
 7. The image inspection device according to claim 1, further comprising: a third inspection section which is arranged at a position which is different from the position of the first inspection section along the inspection object conveyance direction and inspects the image on the front surface of the inspection object; and a fourth inspection section which is arranged at a position which is different from the position of the second inspection section along the inspection object conveyance direction and inspects the image on the back surface of the inspection object, wherein one of the first inspection section and the third inspection section is arranged relatively on the upstream side of the inspection object conveyance direction and inspects the image on the front surface of the inspection object in a linear inspection region which is vertical to the inspection object conveyance direction and is parallel with the conveyance surface and the other of the first inspection section and the third inspection section is relatively arranged on the downstream side of the inspection object conveyance direction and inspects the image on the front surface of the inspection object in a planar inspection region which is parallel with the conveyance surface, and one of the second inspection section and the fourth inspection section is arranged relatively on the upstream side of the inspection object conveyance direction and inspects the image on the back surface of the inspection object in the linear inspection region which is vertical to the inspection object conveyance direction and is parallel with the conveyance surface and the other of the second inspection section and the fourth inspection section is arranged relatively on the downstream side of the inspection object conveyance direction and inspects the image on the back surface of the inspection object in the planar inspection region which is parallel with the conveyance surface.
 8. The image inspection device according to claim 7, wherein the other of the first inspection section and the third inspection section is movable in a direction which is parallel with the linear inspection region, and the other of the second inspection section and the fourth inspection section is movable in a direction which is parallel with the linear inspection region.
 9. The image inspection device according to claim 1, wherein on at least one of the first conveyance unit and the second conveyance unit, at least one of the first inspection section and the second inspection section is installed on at least either an upstream-side end or a downstream-side end of the inspection object conveyance direction.
 10. The image inspection device according to claim 9, wherein at least one of the first inspection section and the second inspection section is installed on the downstream-side end of at least one of the first conveyance unit and the second conveyance unit.
 11. The image inspection device according to claim 9, wherein at least one of the first inspection section and the second inspection section is installed on the upstream-side end of at least one of the first conveyance unit and the second conveyance unit. 